CVE-2025-66488 Discourse allows script execution in uploaded HTML/XML files on S3

Discourse is an open source discussion platform. A vulnerability present in versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 affects anyone who uses S3 for uploads. While scripts may be executed, they will only be run in the context of the S3/CDN domain, with no site credentials...

PT-2026-5176

Discourse is an open source discussion platform. A vulnerability present in versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 affects anyone who uses S3 for uploads. While scripts may be executed, they will only be run in the context of the S3/CDN domain, with no site credentials...

Discourse security vulnerabilities

Discourse is an open-source community discussion platform developed by Discourse. This platform includes features such as communities, email, and chat rooms. Vulnerabilities exist in versions of Discourse prior to 3.5.4, as well as versions prior to 2025.11.2, 2025.12.1, and 2026.1.0. These...